Load Calculations - Branch and Feeder Circuits (Chapter 1)
Jeremiah
Terms in this set (53)
The maximum current in amperes that a conductor can carry continuously under the
Ampacity
conditions of use without exceeding its temperature rating
circuit conductors between the final overcurrent device protecting the circuit and the
Branch circuit
outlet(s)
continuous load load where the maximum current is expected to continue for three hours or more
unit of an electrical system, other than a conductor, that carries or controls electric
device
energy as its principal function
individual branch circuit branch circuit that supplies only one piece of utilization equipment
outlet point on the wiring system at which current is taken to supply utilization equipment
any current in excess of the rated current of equipment or the ampacity of a conductor.
overcurrent
it may result from overload, short circuit, or ground fault.
contact device installed at an outlet for connection as a single contact device. a single
receptacle receptacle is a single contact device with no other contact device on the same yoke. a
multiple receptacle is a single device containing two (duplex) or more receptacles.
receptacle outlet outlet where one or more receptacles are installed.
equipment that utilizes electric energy for electronic, chemical, heating, lighting,
utilization equipment
electromechanical, or similar purposes.
what is the maximum continuous load that 20A x 80% or .80 = 16A (continuous loads are calculated at 125% of the maximum current
may be connected to a 20A, 120V fuse? rating of the load. the reciprocal of 125% is equivalent to 80%)
The voltage drop for a 208V, 1 ott circuit with VD (Voltage Drop) = (2xLxRxI) / 1000, L- load center or total length in feet, R-
a load of 28A, using No. 8 stranded copper conductor resistance (NEC chapter 9, table 8), I- current. (2x160ftx.776x80A)/1000 =
conductors at the circuit length of 160' is....... 6.97V
The ampacity of a 120V, 1 ott load rated at 800VA / 120V = 6.67A
800VA is.....
utilization equipment, generally other than industrial, normally built in standardized
Appliance sizes or types, that is installed or connected as a unit to perform one or more functions
such as clothes washing, air conditioning, food mixing, deep frying, or other purposes
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